Method of making electronic tags

ABSTRACT

This invention relates to a deactivatable tag useable with an electronic article surveillance system and comprised of planar conductive material cut into a pair of inverse, first and second spiral conductors wrapped about each other and positioned for capacitive and inductive coupling. The invention also relates to method of making tage wherein conductors are cut from a planar web of conductive material in a continuous process in a manner that the cutting results in the formation of two spiral conductors without accompanying waste of conductive material, and thereafter positioning the conductors to provide resonant circuits. The conductors of each pair are connected by welding to provide a reliable circuit.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of copending U.S. patentapplication Ser. No. 81,096 filed Aug. 3, 1987 of S. Eugene Benge whichis a continuation-in-part of copending U.S. patent application Ser. No.41,556 filed Apr. 22, 1987 of S. Eugene Benge, Warren J. Pape andRichard S. Vuketich, which is a is a continuation-in-part of copendingU.S. patent application Ser. No. 06/912,466 filed Sept. 29, 1986 of S.Eugene Benge and Robert Lee Froning, now U.S. Pat. No. 4,717,438 grantedJan. 5, 1988, all of said applications having been assigned to MonarchMarking Systems, Inc.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the art of resonant tags used in electronicarticle surveillance systems and to method of making such tags.

2. Brief Description of the Prior Art

The following patents are made of record: U.S. Pat. No. 3,240,647 toMorgan granted Mar. 15, 1966; U.S. Pat. No. 3,624,631 to Chomet grantedNov. 30, 1971; U.S. Pat. No. 3,810,147 to Lichtblau granted May 7, 1974;U.S. Pat. No. 3,913,219 to Lichtblau granted Oct. 21, 1975; U.S. Pat.No. 4,369,557 to Vandebult granted Jan. 25, 1983; U.S. Pat. No.4,482,874 to Rubertus et al granted Nov. 13, 1984; U.S. Pat. No.4,541,559 to O'Brien granted Sept. 17, 1985; U.S. Pat. No. 4,555,414 toHoover granted Nov. 26, 1985; U.S. Pat. No. 4,555,291 to Tait et algranted Nov. 26, 1985; U.S. Pat. No. 4,567,473 to Lichtblau granted Jan.28, 1986; and French Pat. No. 2,412,923 to Degueldre.

SUMMARY OF THE INVENTION

This invention relates to improved, reliable methods of making tags foruse in an electronic article surveillance system. This invention alsorelates to improved tags for use in such systems.

It is a feature of the invention to provide an improved method of makingsuch tags which typically include a pair of conductors spaced bydielectric material. The connectors, both of which are preferablyspiral, are locally welded to each other and, as thus connected, providea detectable resonant circuit. It is preferred that the conductors areboth inductively coupled and that there is distributed capacitancebetween the conductors. It is also preferred that the place or placeswhere the spiral conductors are welded be free of any dielectric,adhesive or other materials that could hinder the formation of a goodweld. It is also preferred that the welding be performed at atemperature and/or at a location which would not adversely affect eitherthe resonant circuit or the means for deactivating the resonant circuit.

It is a feature of the invention to provide improved methods of makingtags with detectable resonant circuits economically on a mass productionbasis, wherein conductors used in making each circuit are connected bywelding to provide a reliable connection.

It is another feature of the invention to make tags with resonantcircuits using connected conductors, in which the conductors areconnected without the need for staking.

It is also a feature of the invention to provide an electronic articlesurveillance tag with a resonant circuit of improved reliability. Theresonant circuit is made by welding portions of two conductors to eachother. The welding is performed by heating welding material dispersedbetween adjacent connector portions of the connectors. Alternatively,the connector portions can be heated and fused locally as by a laserbeam or other suitable contact or non-contact heater.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a tag in accordance with anembodiment of the invention;

FIG. 2 is a fragmentary sectional view of the tag shown in FIG. 1;

FIG. 3 is a diagrammatic perspective view illustrating method of makinga tag in accordance with the invention;

FIG. 4 is a diagrammatic top plan view showing a mask having beenapplied to a first adhesive coated web and showing an electricallyconductive web being laminated to the masked first adhesive coated web;

FIG. 5 is a diagrammatic top plan view showing the conductive web havingbeen cut to provide first and second pairs of conductors and showing amasked second adhesive coated web being laminated to the conductive web;

FIG. 6 is a diagrammatic top plan view showing the first coated web withthe first conductors adhered thereto being separated relative to thesecond coated web with the second conductors adhered thereto, andshowing further the first coated web having been recoated with adhesiveand two webs of dielectric being laminated to the recoated first coatedweb, and showing the dialectric webs having been coated with adhesive;

FIG. 7 is a diagrammatic top plan view showing the second coated webwith the second conductors adhered thereto having been shifted andlaminated over and to the dialectric webs and to the first coated webwith the first conductors to provide a composite tag web, showing thestaking of the first and second conductors of each tag to provideresonant circuits for each tag, and showing slitting of the compositetag web to provide a plural series of composite tag webs;

FIG. 8 is a vertically exploded view showing the first and second coatedwebs with the first and second conductors that result from cutting theelectrically conductive web spirally;

FIG. 9 is a top plan view showing the first and second coated websshifted by a distance equal to the width of one conductor spiral plusthe width of one conductor;

FIG. 10 is a top plan view of two tags with the dialectric web shown inphantom lines;

FIG. 11 is a fragmentary perspective view which, when taken togetherwith the preceding figures of the drawings, illustrates an improvedmethod of making deactivatable tags;

FIG. 12 is a fragmentary top plan view taken along line 12--12 of FIG.11;

FIG. 13 is a sectional view taken along line 13--13 of FIG. 12;

FIG. 14 is a fragmentary perspective view similar to FIG. 1, but showingone embodiment of structure for deactivating the tag;

FIG. 15 is a fragmentary top plan view of the tag shown in FIG. 14;

FIG. 16 is a fragmentary perspective view which, taken together withFIGS. 1 through 10, illustrated an alternative improved method of makingdeactivatable tags;

FIG. 17 is a fragmentary top plan view taken along line 17--17 of FIG.16;

FIG. 18 is a sectional view taken along line 18--18 of FIG. 17;

FIG. 19 is a fragmentary perspective view similar to FIG. 14 but showinganother embodiment of structure for deactivating the tag;

FIG. 20 is a fragmentary top plan view of the tag shown in FIG. 19;

FIG. 21 is a sectional view similar to FIG. 18 but showing analternative structure for deactivating the tag;

FIG. 22 is a top plan view of an alternative cut pattern for the web ofconductive material corresponding generally to D in FIG. 5;

FIG. 23 is a top plan view of the alternative cut pattern with one-halfof the conductive material removed and corresponding generally to G inFIG. 6;

FIG. 24 is a diagrammatic perspective view showing the manner in whichthe webs of deactivating material are cut into stripes or strips;

FIG. 25 is a top plan view of a pair of longitudinally spaced resonantcircuits with separate respective deactivator strips;

FIG. 26 is a fragmentary, diagrammatic, perspective view showing theportion of a tag making process which incorporates the presentinvention;

FIG. 27 is a top plan view similar to FIG. 25, but incorporating theinvention also illustrated in FIG. 26;

FIG. 28 is a sectional view taken generally along line 28--28 of FIG.27;

FIG. 29 is a fragmentary perspective view showing an alternativearrangement for welding the spiral conductors to each other; and

FIG. 30 is a sectional view taken generally along 30--30 of FIG. 29.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring initially to FIG. 1, there is shown an exploded view of a taggenerally indicated at 19. The tag 19 is shown to include a sheet 20Thaving pressure sensitive adhesive 21 and 22 on opposite faces thereof.A mask 23 in a spiral pattern covers a portion of the adhesive 21 and arelease sheet 24T is releasably adhered to the adhesive 22. The mask 23renders the adhesive 21 which it covers non-tacky or substantially so. Aconductor spiral indicated generally at 25 includes a spiral conductor26 having a number of turns. The conductor 26 is of substantially thesame width throughout its length except for a connector bar 27 at theouter end portion of the conductor spiral 26. There is a sheet ofdielectric 28T over and adhered to the conductor spiral 25 and theunderlying sheet 20T by means of adhesive 29. A conductor spiralgenerally indicated at 30 includes a spiral conductor 31 having a numberof turns. The conductor 31 is adhered to adhesive 29 on the dielectric28T. The conductor 31 is substantially the same width throughout itslength except for a connector bar 32 at the outer end portion of theconductor spiral 30. The conductor spirals 25 and 30 are generallyaligned in face-to-face relationship except for portions 33 which arenot face-to-face with the conductor 26 and except for portions 35 whichare not face-to-face with the conductor 31. A sheet 37T has a coating ofa pressure sensitive adhesive 38 masked off in a spiral pattern 39. Theexposed adhesive 38' is aligned with the conductor spiral 30. Adhesiveis shown in FIG. 1 by heavy stippling and the masking is shown in FIG. 1by light stippling with cross-hatching. The connector bars 27 and 32 areelectrically connected, as for example by staking 90. It should be notedthat the staking 90 occurs where connector bars 27 and 32 are separatedonly by adhesive 29. There is no paper, film or the like between theconnector bars 27 and 32. Accordingly, the staking disclosed in thepresent application is reliable.

With reference to FIG. 3, there is shown diagrammatically a method formaking the tag 19 shown in FIGS. 1 and 2. A roll 40 is shown to becomprised of a composite web 41 having a web 20 with a full-gum orcontinuous coatings of pressure sensitive adhesive 21 and 22 on oppositefaces thereof. The web 20 is "double-faced" with adhesive. A releaseliner or web 42 is releasably adhered to the upper side of the web 20 bythe pressure sensitive adhesive 21, and the underside of the web 20 hasa release liner or web 24 releasably adhered to the pressure sensitiveadhesive 22. As shown, the release liner 42 is delaminated from the web20 to expose the adhesive 21. The adhesive coated web 20 together withthe release liner 24 pass partially about a sandpaper roll 43 andbetween a pattern roll 44 and a back-up roll 45 where mask patterns 23are applied onto the adhesive 21 to provide longitudinally recurringadhesive patterns 21'. Masking material from a fountain 46 is applied tothe pattern roll 44. With reference to FIG. 4, the portion marked Arepresents the portion of the web 20 immediately upstream of the patternroll 44. The portion marked B shows the mask patterns 23 printed by theroll 44. The patterns 23 are represented by cross-hatching in FIG. 4.With reference to FIG. 3, the web 20 now passes through a dryer 47 wherethe mask patterns 23 are dried or cured. The adhesive 21 is renderednon-tacky at the mask patterns 23. A web 49 of planar, electricallyconductive material such as copper or aluminum from a roll 48 islaminated onto the coated web 20 as they pass between laminating rolls50 and 50'. Reference character C in FIG. 4 denotes the line wherelamination of the webs 20 and 49 occurs. With reference to FIG. 3, thelaminated webs 20 and 49 now pass between a cutting roll 51 havingcutting blades 52 and a back-up roll 53. The blades 52 cut completelythrough the conductive material web 49 but preferably do not cut intothe web 20. The blades 52 cut the web 49 into a plurality of series ofpatterns 25 and 30 best shown in the portion marked D in FIG. 5. Withreference again to FIG. 3, there is shown a roll 54 comprised of acomposite web 55 having a web 37 with a full-gum or continuous coatingof pressure sensitive adhesive 38 and a release liner 56 releasablyadhered to the adhesive 38 on the web 37. The release liner 56 isseparated from the web 37 and the web 37 passes about a sandpaper roll57. From there the web 37 passes between a pattern roll 58 and a back-uproll 59 where mask patterns 39 are applied onto the adhesive 38 torender the adhesive 38 non-tacky at the mask patterns 39 to providelongitudinally recurring adhesive patterns 38' (FIG. 1). Maskingmaterial from a fountain 60 is applied to the pattern roll 58. Themasking material of which the patterns 23 and 39 are comprised is acommercially available printable adhesive deadener such as sold underthe name "Aqua Superadhesive Deadener" by Environmental Inks and CoatingCorp, Morganton, N.C. From there the web 37 passes partially about aroll 61 and through a dryer 62 where the mask patterns 39 are dried orcured. The adhesive 38 is rendered non-tacky at the mask patterns 39.From there the webs 20, 49 and 37 pass between laminating rolls 63 and64. FIG. 5 shows that lamination occurs along line E where the web 37meets the web 49. When thus laminated, each adhesive pattern 21'registers only with an overlying conductor spiral 25 and each adhesivepattern 38' registers only with an underlying conductor spiral 30.

The webs 20, 37 and 49 pass successively partially about rolls 65 and 66and from there the web 37 delaminates from the web 20 and passespartially about a roll 67. At the place of delamination, the web 49separates into two webs of conductor spirals 25 and 30. As shown in FIG.6, delamination occurs along the line marked F. When delaminationoccurs, the conductor spirals 30 adhere to the adhesive patterns 38' onthe web 37, and the conductor spirals 25 adhere to the adhesive patterns21' on the web 20. Thus, the conductor spirals 30 extend in one web andthe spirals 25 extend in another web. The web 20 passes partially aboutrolls 68, 69 and 70 and from there pass between an adhesive coating roll71 and a back-up roll 72. Adhesive 29 from a fountain 73 is applied tothe roll 71 which in turn applies a uniform or continuous coating ofadhesive 29 to the web 20 and over conductive spirals 25. The portionmarked G in FIG. 6 shows the portion of the web 20 and conductor spirals25 between the spaced rolls 66 and 72. The portion marked H shows theportion of the web 20 between the spaced rolls 72 and 74. With referenceto FIG. 3, the web 20 passes through a dryer 75 where the adhesive 29 isdried. A plurality, specifically two laterally spaced dialectric webs28a and 28b wound in rolls 76 and 77 are laminated to the web 20 as thewebs 20, 28a and 28b pass between the rolls 74 and 74'. This laminatingoccurs along reference line I indicated in FIG. 6. With reference toFIG. 3, the web 20 with the conductor spirals 25 and the dialectric webs28a and 28b pass about rolls 78 and 79 and pass between an adhesiveapplicator roll 80 and a back-up roll 81. The roll 80 applies adhesive29' received from a fountain 83 to the webs 28a and 28b and to theportions of the web 20 not covered thereby. From there, the webs 20, 28aand 28b pass through a dryer 84 and partially about a roll 85.

The web 37 which had been separated from the web 20 is laminated at thenip of laminating rolls 86 and 87 along a line marked J in FIG. 7 toprovide a composite tag web generally indicated at 88. The webs 20, 28a,28b and 37 are laminated between rolls 86 and 87 after the conductorspirals 30 have been shifted longitudinally with respect to theconductor spirals 25 so that each conductor spiral 30 is aligned orregistered with an underlying conductor spiral 25. The shifting can beequal to the pitch of one conductor spiral pattern as indicated at p(FIG. 9) plus the width w of one conductor, or by odd multiples of thepitch p plus the width w of one conductor. Thus, each pair of conductorspirals 25 and 30 is capable of making a resonant circuit detectable byan appropriate article surveillance circuit.

FIG. 8 shows the web 20 and the web 37 rotated apart by 180°. FIG. 9shows the web 20 and the web 37 rotated apart by 180° and as having beenshifted with respect to each other so that the conductor spirals 25 and30 are aligned. As best shown in FIG. 10, the dialectric 28a terminatesshort of stakes 90 resulting from the staking operation. By thisarrangement the stakes 90 do not pass through the dielectric 28a (or28b). FIG. 10 shows the conductor spirals 25 and 30 substantiallyentirely overlapped or aligned with each other, except as indicated at35 for the conductor spiral 25 and as indicated at 33 for the conductorspiral 30. Each circuit is completed by staking the conductor bars 27and 32 to each other as indicated at 90 or by other suitable means. Thestaking 90 is performed by four spiked wheels 89 which make four stakelines 90 in the composite web 88. The spiked wheels 89 pierce throughthe conductor bars 27 and 32 and thus bring the conductor bars 27 and 32into electrically coupled relationship. The web composite 88 is slitinto a plurality of narrow webs 91 and 92 by slitter knife 93 and excessmaterial 94 is trimmed by slitter knives 95. The webs 91 and 92 are nextcut through up to but not into the release liner 24 by knives on acutter roll 96, unless it is desired to cut the tags T into separatedtags in which event the web 88 is completely severed transversely. Asshown, the webs 91 and 92 continue on and pass about respective rolls 97and 98 and are wound into rolls 99 and 100. As shown in FIG. 7, thestaking 90 takes place along a line marked K and the slitting takesplace along a line marked L.

The sheet 37T, the dialectric 28T, the sheet 20T and the sheet 24T arerespectively provided by cutting the web 37, the web 28a (or 28b), theweb 20 and the web 24.

FIG. 11 is essentially a duplicate of a portion of FIG. 3, but a pair ofcoating and drying stations generally indicated at 111 and 112 whererespective coatings 113 and 114 in the form of continuous stripes areprinted and dried. The coating 113 is conductive and is applied directlyonto the pressure sensitive adhesive 38 on the web 37. The coatings 114are wider than the respective coatings 113 which they cover to assureelectrical isolation, as best shown in FIGS. 12 and 13. The coatings 114are composed of a normally non-conductive activatable material. Theremainder of the process is the same as the process taught in connectionwith FIGS. 1 through 10.

With reference to FIGS. 14 and 15, there is shown a fragment of thefinished tag 37T' with the coatings 113 and 114 having been severed asthe tag 37T' is severed from the tag web as indicated at 113T and 114Trespectively. As shown the coating 113T is of constant width andthickness throughout its length and the coating 114T is of constantwidth and thickness but is wider than the coating 113T. The coating 113Twhich is conductive is thus electrically isolated from the conductorspiral 30. The coatings 113T and 114T comprise an activatable connectionAC which can be activated by subjecting the tag to a high level ofenergy above that for causing the resonant circuit to be detected at aninterrogation zone.

FIG. 16 is essentially a duplicate of a portion of FIG. 3, but a pair ofwebs 118 and 119 are adhered to the adhesive 38 on the web 37. The webs118 and 119 are wound onto spaced reels 120 and 121. The webs 118 and119 pass from the reels 120 and 121 partially about a roll 122. The webs118 and 119 are spaced apart from each other and from the side edges ofthe web 37. The webs 118 and 119 are identical in construction, and eachincludes a thin layer of conductive material 123 such as copper oraluminum on a layer of paper 123', a high temperature, normallynon-conductive, activatable, conductor-containing layer 124, and a lowtemperature, normally non-conductive, activatable, conductor-containinglayer 125. The layers 124 and 125 contain conductors such as metalparticles or encapsulated carbon. The layer 125 bonds readily whenheated, so a drum heater 115 is positioned downstream of the roll 67(FIGS. 3 and 16) and upstream of the rolls 86 and 87 (FIG. 3). Theheated circuits 30, heat the layer 125 and a bond is formed between thecircuits 30 and the layer 125. Rolls 116 and 117 (FIG. 16) guide the web37 about the drum heater 115. The heating of the layer 125 has sometendency to break down the normally non-conductive nature of the layer125, but this is not serious because the layer 124 is not broken down oractivated by heat from the drum heater 115.

With reference to FIGS. 19 and 20, there is shown a fragment of afinished tag 37T" with the webs 118 and 119 having been severed so as tobe coextensive with the tag 37T" and is indicated at 118T. The web stripor stripe 118T includes the paper layer 123', the conductive layer orconductor 123 and the normally non-conductive layers 124 and 125. Thelayers 123, 124 and 125 are shown to be of the same width and comprisean activatable connection AC. Both coatings 124 and 125 electricallyisolate the conductor 123 form the conductor spiral 30. In otherrespects the tag 37T" is identical to the tag 37T and is made by thesame process as depicted for example in FIG. 3.

The embodiment of FIG. 21 is identical to the embodiment of FIGS. 16through 20 except that instead of the webs 118 and 119 there are a pairof webs comprised of flat bands, one of which is shown in FIG. 21 and isdepicted at 118'. The band 118' is comprised of a web or band conductor126 of a conductive material such as copper enclosed in a thin coatingof a non-conductive material 127. The band 118' comprises an activatableconnection AC. As seen in FIG. 21, the upper surface of the coating 127electrically isolates the conductor 126 from the conductor spiral 30.The band 118' is processed according to one specific embodiment, bystarting with coated motor winding wire, Specification No. 8046 obtainedfrom the Belden Company, Geneva, Ill. 60134 U.S.A. and having a diameterof about 0.004 inch with an insulating coating of about 0.0005,flattening the wire between a pair of rolls into a thin band having athickness of 0.0006 inch. Thus processed, the insulating coating isweakened to a degree which breaks down when the resulting tag issubjected to a sufficiently high energy level signal. The coating 118'is thus termed a "breakdown coating" because it acts as an insulatorwhen the tag is subjected to an interrogation signal at a first energylevel but no longer acts as an electrical insulator when subjected to asufficently higher energy level signal. The conductor 126 accordinglyacts to short out the inductor 30 at the higher energy level signal.

The embodiments depicted in FIGS. 11 through 20 and described inconnection therewith enable the tag 37T' or 37T" to be detected in aninterrogation zone when subjected to a radio frequency signal at or nearthe resonant frequency of the resonant circuit. By sufficientlyincreasing the energy level of the signal, the normally non-conductivecoating 114 (or 114T), or 124 and 125 becomes conductive to alter theresponse of the resonant circuit. This is accomplished in a specificembodiment by using a normally non-conductive coating to provide an openshort-circuit between different portions of the conductor spiral 30.

When the tag is subjected to a high level of energy, in the embodimentsof FIGS. 11 through 15, and 16 through 20 the normally non-conductivecoating becomes conductive and shorts out the inductor. Thus, theresonant circuit is no longer able to resonate at the proper frequencyand is unable to be detected by the receiver in the interrogation zone.

While the illustrated embodiments disclose the activatable connection ACprovided by an additional conductor as extending across all the turns ofthe conductor spiral 30 and by a normally non-conductive material orbreakdown insulation electrically isolating the conductor from theconductor spiral 30 and also extending across all of the turns of theconductor spiral 30, the invention is not to be considered limitedthereby.

By way of example, not limitation, examples of the various coatings arestated below:

I. For the embodiment of FIGS. 11 through 15

A. Examples of the normally non-conductive coating 114 are:

    ______________________________________                                                              Parts by Weight                                         ______________________________________                                        Example 1                                                                     cellulose acetate (C.A.)                                                                              60                                                    powder (E-398-3)                                                              acetone                 300                                                   Mixing procedure: Solvate C.A. powder                                         in acetone with stirring.                                                     C.A./copper dispersion                                                        above C.A. solution (16% T.S.)                                                                        15                                                    copper 8620 powder      2.5                                                   Mixing procedure: Add copper powder to                                        C.A. solution with adequate stirring to                                       effect a smooth metallic dispersion.                                          Example 2                                                                     acrylvid B-48N          30                                                    (45% in toluene)                                                              acetone                 20                                                    isopropanol             3                                                     Above solution (25% T.S.)                                                                             10                                                    copper 8620 powder      5                                                     Mixing procedure: disperse copper powder                                      into B-48N solution (Percent copper powder                                    is 60-70% on dry weight basis.)                                               ______________________________________                                    

B. Examples of the conductive coating 113 are:

    ______________________________________                                                              Parts by Weight                                         ______________________________________                                        Example 1                                                                     acryloid B-67 acrylic   25                                                    (45% in naptha)                                                               naptha                  16                                                    silflake #237 metal powder                                                                            42                                                    Mixing procedure: add metal powder to                                         solvent and wet out. Add solvated acrylic                                     and stir well to disperse. Mix or shake                                       well prior to use. (75% to 85% conductive                                     metal on dry weight basis.)                                                   Example 2                                                                     acryloid NAD-10         10                                                    (40% in naptha)                                                               silflake #237 metal powder                                                                            20                                                    Mixing procedure: Add metal powder to                                         acrylic dispersion with stirring.                                             Example 3                                                                     S & V aqueous foil ink  5                                                     OFG 11525 (37% T.S.)                                                          silflake #237 metal powder                                                                            8                                                     Mixing procedure: Add metal powder to                                         aqueous dispersion slowly with adequate                                       agitation to effect a smooth metallic                                         dispersion.                                                                   ______________________________________                                    

I. For the embodiment of FIGS. 16 through 20

A. Examples of the low temperature coating 125 are:

    ______________________________________                                                              Parts by Weight                                         ______________________________________                                        Example 1                                                                     acryloid NAD-10 dispersion                                                                            10                                                    (30% T. Solids)                                                               naptha                  2                                                     copper 8620 copper powder                                                                             5                                                     Mixing procedure: wet copper powder with                                      Naptha and disperse completely. Add NAD-10                                    dispersion slowly with stirring. Mix well                                     or shake before use.                                                          Example 2                                                                     polyester resin         28                                                    (K-1979)                                                                      ethanol                 10                                                    isopropanol             10                                                    ethyl acetate           20                                                    above polyester solution                                                                              10                                                    copper 8620 powder      2.5                                                   Mixing procedure: add copper powder to                                        polyester solution while stirring to effect                                   a smooth metallic dispersion.                                                 (48% copper powder on dry basis)                                              ______________________________________                                    

B. Examples of the high temperature coating 124 are:

    ______________________________________                                        Example 1                                                                     cellulose acetate butyrate                                                                              40                                                  (C.A.B.)(551-0.2)                                                             toluene                   115                                                 Ethyl Alcohol             21                                                  Above C.A.B. solution     10                                                  (22.7%)                                                                       toluene                    2                                                  copper 8620 copper powder  5                                                  Mixing procedure: wet copper powder with                                      solvent and add C.A.B. solution with                                          stirring.                                                                     Example 2                                                                     acryloid B-48N            30                                                  (45% in toluene)                                                              acetone                   20                                                  isopropanol                3                                                  Above solution (25% T.S.) 10                                                  copper 8620 copper powder  5                                                  (Dry weight basis - copper                                                    is 60-70%)                                                                    Mixing procedure: add copper powder to                                        above solution with proper agitation to                                       effect a smooth metallic dispersion.                                          ______________________________________                                    

The materials used in the above examples are obtainable from thefollowing suppliers:

Acryloid AND-10, Acryloid B-48N and Acryloid B-67, Rohm & Hass,Philadelphia, Pa.;

Cellulose Acetate (E-398-3) and Cellulose Acetate Butyrate (551-0.2),Eastman Chemical Products, Inc., Kingsport, Tenn.;

Copper 8620, U.S. Bronze, Flemington, N.J.;

Silflake #237, Handy & Harmon, Fairfield, Conn.;

Krumbhaar K-1979, Lawter International, Inc., Northbrook, Ill.;

Aqeuous foil ink OFG 11525, Sinclair & Valentine, St. Paul, Minn.

FIGS. 22 through 25 depict an improved method over the embodiment ofFIGS. 11 through 15, over the embodiment of FIGS. 16 through 20, andover the embodiment of FIG. 21. The method of the embodiment of FIGS. 22through 25 relates to the formation of longitudinally spaceddeactivatable resonant circuits arranged in a web. The longitudinalspacing of the resonant circuits assures that electrostatic charge thatcan prematurely deactivate one resonant circuit in the web cannot arclongitudinally to the other resonant circuits in the web to cause theirpremature deactivation. Where possible, the same reference characterwill be used in the embodiment of FIGS. 22 through 25 as in theembodiment of FIGS. 16 through 20 to designate components having thesame general construction and function, but increased by 200. It will beappreciated that reference is also made to FIGS. 3, 5 and 6.

With reference initially to FIG. 22, web 249 of planar, electricallyconductive material is cut in patterns of conductor spirals 400 and 401.The cut patterns include lateral or transverse lines of completesevering 402. The conductor spirals 400 and 401 are generally similar tothe conductor spirals 25 and 30, however, inspection of FIG. 5 willindicate that all conductor spirals 25 and 30 are in very closeproximity to each other in the longitudinal direction, being spaced onlyby knife cuts themselves. In addition, spirals 25 are connected to eachother and spirals 30 are connected to each other. In contrast, in theembodiment of FIGS. 22 through 25, only the conductor spirals 400 and401 between adjacent lines of complete severing 402 are connected toeach other. In the method of FIGS. 22 through 25, reference may be hadto FIG. 3 which shows that the conductor spiral webs 20 and 37 areseparated as they pass partly about roll 66, thereafter dielectricmaterial webs 28a and 28b are applied, the webs 20 and 37 are shiftedlongitudinally by the pitch of one conductor spiral 400 (or 401) plusthe width of one conductor, and thereafter the webs 20 and 37 arere-laminated as they pass between rolls 86 and 87.

As is evident from FIG. 23, once the web of resonant circuits 401 isstripped away, the resultant web 220 has pairs of resonant circuits 401that are longitudinally spaced apart. In like manner, the pairs ofresonant circuits 400 in the stripped away web (corresponding to the web37 in FIG. 3), are also spaced apart longitudinally.

The method of the embodiment of FIGS. 22 through 25, relates toproduction of deactivatable tags. The illustrated arrangement fordeactivating the tags utilizes the arrangement taught in the embodimentof FIGS. 16 through 20 with the exception that the deactivator webs 318and 319 (corresponding to the deactivator webs 118 and 119 in FIG. 16for example), are separated into longitudinally spaced deactivatorstrips or stripes 318' and 319'. The separation is accomplished inaccordance with the specific embodiment shown in FIG. 24, by punchingout portions or holes 407 of the web 238 and the deactivator webs 318and 319. For this purpose, a diagrammatically illustrated rotary punch403 has punches 405 and the rotary die 404 has cooperating die holes406. The resultant holes 407 are wider than the spacing between theresonant circuits. The holes 407 are thus registered with the margins ofthe longitudinally spaced resonant circuits are shown in FIG. 25. Thus,static electricity cannot arc between resonant circuits in alongitudinal direction and static electricity cannot arc betweendeactivator strips 318' (or 319').

The invention of the embodiments of FIGS. 26 through 28, and 29 and 30has applicability in general to tags with resonant circuits withgenerally spaced but connected conductors. For example, the invention isuseful in the embodiments of FIGS. 1 through 10, 11 through 13, 14through 20, 21 and 22 through 25. The invention is not limited toapplications involving a pair of spiral conductors. It is useful forexample in resonant circuits where at least one of the conductors is nota spiral. This type of a circuit is shown for example in U.S. Pat. No.3,913,219. The invention is, however, illustrated with the structureaccording to the most preferred embodiment of FIGS. 22 through 25.

With reference initially to FIG. 26, there are illustrated several ofthe steps in the improved process. It is to be understood that othersteps in the process are illustrated in other figures, for example FIGS.3 and 16. It is seen in FIG. 3 that the roll 71 applies a coating ofadhesive 29 fully across the web 24 and that the roll 80 applies acoating of adhesive 29' fully across the dielectric webs 28a and 28b,but also fully across the exposed portions of the web 24. This meansthat when the staking occurs as illustrated at 90, the spiked wheels 89are required to pass through adhesive and also that the spiralconductors are spaced by that adhesive except where the staking occurs.By a construction not shown, and with respect to the embodiments ofFIGS. 26 through 28, and 29 and 30, the roll 29 is patterned so it willnot apply adhesive to the web 24 except in the path of the dielectricwebs 28a and 28b. Roll 80' is identical to the roll 80 except it ispatterned to apply adhesive 29' only to the upper sides of thedielectric webs 28a and 28b so that portions 24(1), 24(2) and 24(3) ofthe web 24 are free of adhesive. From there the web 24 and associatedwebs 28a and 28b pass through a drier 84 and partly around a roll 85. Afountain 500 has a roll 501 cooperating with a back-up roll 502 todeposit or print a welding material 503 onto the connector portions 400cof spiral conductors 400 in a predetermined repetitive pattern. It ispreferred that two spaced spots of the welding material 503 be appliedto each connector portion 400c. As shown, once the welding material 503has been applied, the web 24 is laminated to the web 37 as they passbetween rolls 504 and 505. From there the combined webs 24 and 37 passpartially around and in contact with a drum heater 506 and from therepartially about rolls 507 and 508 to slitters 93 and 95. From there thetag web 89 can be acted upon by transverse cutter 96 and the resultingnarrow webs rolled into individual rolls. The drum heater 506 causes theconnector portions 400c and 401c to be welded to each other to make goodelectrical connection. The expression "welding" as used herein includeswhat is sometimes referred to as "soldering". The heater 506 heats thewelding material to the temperature where it fuses to the connectorportions 400 and 401 to each other but below the temperature where theresonant circuit is degraded or where the activatable connection ACcauses deactivation of the resonant circuit. By way of example, notlimitation, the welding material fuses at 96° C. and the breakdowncoating 114 for example breaks down at 103° C. The welding material iscomprised of 80% by weight of metal alloy and of 20% by weight of fluxand is designated BI52PRMAA4 and sold by Multicore Solders Inc.,Cantiague Rock Road, Westbury N.Y. 11590. The metal alloy contains 15%tin, 33% lead and 52% bismuth. The 20% by weight of flux comprises 10.3%resin, 8.4% glycol, 0.3% activators and 1.0% gelling agent.

In an alternative embodiment, the tags can be made as illustrated forexample in FIGS. 3 and 16 except instead of applying the weldingmaterial 503, the connector portions 400C and 401C are connected bywelding using localized heat to bring the temperature of the connectorportions 400 and 401 to the melting point. The resulting weld is shownat 509. This can be accomplished for example by a laser beam. Laser guns510 illustrated in FIG. 29 are operated to effect the welds 509.

Other embodiments and modifications of the invention will suggestthemselves to those skilled in the art, and all such of these as comewithin the spirit of this invention are included within its scope asbest defined by the appended claims.

I claim:
 1. Method of making tags for use in an electronic articlesurveillance system, comprising the steps of: providing a web having aseries of first conductors, providing another web having a series ofsecond conductors, positioning the webs so that the first and secondconductors of each pair are spaced apart by dielectric material, andusing a laser beam to weld adjacent portions of the first and secondconductors of each pair so that each pair provides a detectable resonantcircuit.
 2. Method of making tags for use in an electronic articlesurveillance system, comprising the steps of: providing a series ofpairs of first and second conductors spaced apart by dielectricmaterial, with each first and second conductor having a connectorportion free of dielectric material, and using a laser beam to weld theconnector portions of each pair to each other to provide a series ofdetectable resonant circuits.
 3. Method of making tags for use in anelectronic article surveillance system, comprising the steps of:providing a series of pairs of first and second conductors spaced apartby dielectric material and adhesively attached, with each first andsecond conductors having a connector portion free of dielectric materialand free of adhesive, and welding the connector portions to each otherto provide a series of detectable resonant circuits.
 4. Method of makingtags for use in an electronic article surveillance system, comprisingthe steps of: providing a web having a series of first conductors,providing another web having a series of second conductors, wherein atleast one of the conductors is a spiral conductor, depositing weldingmaterial on each conductor of one of said series, positioning adeactivator adjacent one conductor of one of said series, wherein thedeactivator includes heat activatable material rendered conductive bythe application of heat, positioning the webs so that the first andsecond conductors are in adjacent pairs spaced apart by dielectricmaterial to provide a tag web, and applying heat to the tag web at atemperature high enough to cause the welding material to weld theconductors to each other to provide a detectable resonant circuit butlow enough to prevent the activatable material from being renderedconductive.